KR20230085162A - Calcium carbonate particulate matter with a low content of water-soluble magnesium ions - Google Patents

Abstract

The present disclosure relates to a calcium carbonate particulate material comprising less than about 170 ppm water-soluble magnesium ions, based on the total amount of calcium carbonate particulate matter, wherein the amount of water-soluble magnesium ions is determined using the method described herein. The present disclosure further includes a method for producing a calcium carbonate particulate material according to the present disclosure, and a calcium carbonate particulate material according to the present disclosure or a calcium carbonate particulate material obtainable by the method according to the present disclosure. It relates to a paint composition that

Description

Calcium carbonate particulate matter with a low content of water-soluble magnesium ions

[01] The present disclosure includes a calcium carbonate particulate material having a low content of water-soluble magnesium ions, a method for producing a calcium carbonate particulate material having a low content of water-soluble magnesium ions, and a calcium carbonate particulate material according to the present disclosure. It relates to a paint composition that

[02] Calcium carbonate particulate matter, such as precipitated calcium carbonate (PCC) or grounded calcium carbonate (GCC), has a wide range of applications, for example in compositions such as plastics, paper and paints. used as a filler in Methods for preparing calcium carbonate particulate material are well known in the art. However, due to the large-scale production processes used, it is generally not economically and/or ecologically feasible to eliminate all by-products present in the calcium carbonate particulate material, for example magnesium ions and their respective salts. This is despite the fact that the presence of these by-products often impedes the use of calcium carbonate particulate material in many applications.

[03] For example, when calcium carbonate particulate matter is used in a paint composition having a high pH value, that is, a high alkalinity that is frequently obtained and buffered using water glass, gel formation frequently occurs resulting in a significant increase in viscosity. It was observed that In some cases, the paint composition cannot or at least not be processed further to produce a generally acceptable and homogeneously painted substrate. However, providing a paint composition with a high pH value is one way to reduce microbial growth in the paint composition (which may already have microbial growth during its production and storage), the resulting coating, and the coated surface. In this case, the addition of an organic biocide to the paint composition may no longer be necessary.

[04] Microbial growth can lead to aesthetic degradation of the paint composition and resulting coating, particularly in the presence of mold, powdery mildew, algal and/or bacterial growth, for example. Additionally, enzymes or other components released by such microbial growth may cause physical degradation of the paint composition prior to application and/or physical degradation of the resulting coating. This physical degradation can include an increase in the porosity of the coating or loss of adhesion of the coating to the substrate, which can cause, for example, moisture penetration through the coating on the wood that can lead to microbial decay of the underlying wood. there is. That is, in this case, the paint composition no longer exhibits the properties required therefrom as a coating, such as protecting wood.

[05] As outlined above, one alternative to making a paint composition resistant to microbial growth is to use an organic biocide in the paint composition instead of providing the paint composition with a high pH value. However, due to already existing regulations, ecological reasons and/or customer demand, it may not be possible or desirable to use organic biocides in paint compositions. For example, since January 2020, all interior wall paint compositions have been awarded the Blue Angel label, a German certification for products and services with environmentally friendly aspects, which is considered one of the world's first ecolabels, It is highly relevant to purchasing decisions and is no longer allowed to claim isothiazolinone-based preservatives (biocides) (MIT/BIT/CMIT, etc.).

[06] Therefore, the use of hitherto used organic biocides in paint compositions no longer appears to be a viable option, as future regulations banning the use of further organic biocides are anticipated, and high pH values It appears to be a desirable option to avoid microbial growth in the paint composition and resulting coating.

[07] However, as described above, when calcium carbonate is used as an extender in a paint composition having a high pH value, gel formation occurs frequently, resulting in a significant increase in viscosity. Nevertheless, preference is given to using calcium carbonate instead of TiO ₂ , for example for economic and ecological reasons.

[08] Therefore, there is a need for a calcium carbonate particulate material that can be used in paint compositions having particularly high pH values.

[09] The disclosure of the present invention is defined in the appended claims.

[10] According to a first aspect, there is provided a calcium carbonate particulate material comprising less than about 170 ppm of water-soluble magnesium ions based on the total amount of the calcium carbonate particulate material, wherein the amount of water-soluble magnesium ions is determined using the method described herein. is determined by

[11] According to the second aspect, a method for producing the calcium carbonate particulate material according to the first aspect is provided, which includes:

- providing a calcium carbonate particulate material comprising at least about 170 ppm water soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water soluble magnesium ions is determined using the method described herein; and

- heating the calcium carbonate particulates to a temperature of about 65° C. to about 200° C. for a period of up to about 24 hours.

[12] The process according to the second aspect alternatively,

- providing a calcium carbonate particulate material comprising at least about 170 ppm water soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water soluble magnesium ions is determined using the method described herein; and

- washing the calcium carbonate particulate matter with water.

[13] The process according to the second aspect alternatively,

- providing a calcium carbonate particulate material comprising at least about 170 ppm water soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water soluble magnesium ions is determined using the method described herein;

- washing the calcium carbonate particulate matter with water; and

- heating the calcium carbonate particulate material to a temperature of about 65° C. to about 200° C. for a period of up to about 24 hours after washing.

[14] In a second aspect, the provided calcium carbonate particulate material may contain from about 170 ppm or more to less than about 200 ppm of water-soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water-soluble magnesium ions is described herein Calcium carbonate particulate material determined using methods described herein, or provided, may include at least about 200 ppm of soluble magnesium ions, based on the total amount of calcium carbonate material, wherein the amount of soluble magnesium ions is determined using methods described herein. do.

[15] According to a third aspect, a calcium carbonate particulate material obtainable by the process according to the second aspect is provided.

[16] According to a fourth aspect, a paint composition comprising the calcium carbonate particulate material according to the first or third aspect is provided.

[17] Certain embodiments of the present disclosure may provide one or more of the following advantages:

• the desired low content of soluble magnesium ions in the calcium carbonate particulate matter;

• the desired stability of a paint composition comprising a calcium carbonate particulate material according to the present disclosure;

• easy upscaling of manufacturing processes to large-scale industrial processes;

● An economical and environmentally friendly calcium carbonate material for a variety of applications including the possibility to replace other materials currently used.

[18] Details, examples and embodiments provided in relation to any specific one or more of the recited aspects of the present disclosure apply equally to all aspects of the present disclosure. All possible variant embodiments, examples, and any combination of embodiments described herein are included in the present disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

[19] It is understood that the following description relates to exemplary embodiments of the present disclosure and does not limit the scope of the claims.

[20] Surprisingly, it was found that a calcium carbonate particulate material with a low content of water-soluble magnesium ions can be prepared, and a paint formulation comprising a calcium carbonate particulate material with a low content of water-soluble magnesium ions can have improved stability. lost. As used herein, a "water-soluble magnesium ion" is a magnesium ion released from a water-soluble magnesium salt, which is dependent on the solubility of a given salt in water. The amount of these water-soluble magnesium ions can be measured by the methods described herein.

[21] The amount of water-soluble magnesium ions may be supplied from one or more magnesium compounds such as magnesium salt(s). The one or more magnesium salt(s) may be MgCl ₂ , MgBr ₂ , MgI ₂ , MgSO ₄ , Mg(acetate) ₂ , Mg(ClO ₃ ) ₂ , Mg(ClO ₄ ) ₂ , Mg(BrO ₃ ) ₂ , MgCr ₂ O ₇ , MgSiF ₆ , Mg(HCO ₂ ) ₂ , Mg(IO ₃ ) ₂ , MgMoO ₄ , MgS ₂ O ₃ and their hydrates such as MgCl ₂ , MgCl ₂ 6 H ₂ O, MgBr ₂ , MgBr ₂ 6 H ₂ O, MgI ₂ , MgI 2 8 H 2 O, _{MgSO 4} , MgSO _{4 7} H ₂ O, Mg(acetate) ₂ , Mg(acetate) ₂ 4 H ₂ O, Mg(ClO ₃ ) ₂ , Mg(ClO ₄ ) ₂ , Mg(ClO ₄ ) ₂ 6 H ₂ O, Mg(BrO ₃ ) ₂ , Mg(BrO ₃ ) ₂ 6 H ₂ O, MgCr ₂ O ₇ , MgSiF ₆ , MgSiF ₆ 6 H ₂ O, Mg(HCO ₂ ) ₂ , Mg(HCO ₂ ) ₂ 2 H ₂ O, Mg(IO ₃ ) ₂ , Mg(IO ₃ ) ₂ 4 H ₂ O, MgMoO ₄ , MgS ₂ O ₃ 6 H ₂ O.

How to determine soluble magnesium ion

[22] In the disclosure of the present invention, the content of water-soluble magnesium ions in the calcium carbonate particulate matter is determined by mixing 20 g of the calcium carbonate particulate matter with 200 ml of demineralized water at a temperature of 20° C., and the mixture is subsequently stirred at 400 rpm. Stir on a multi-stirrer for 15 minutes. The slurry is then allowed to settle for 45 minutes and then the filtrate is filtered through a 0.1 um Millipore vacuum filter. If the filtrate is not clear, in one or more subsequent steps, the filtrate is collected on cellulosic filter(s) having half the pore size of the previous filtration step until the filtrate is clear. The resulting filtrate is then analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-OES or ICP-AES) according to DIN EN ISO 11885 using an iCAP 6300 from Thermo-Fisher. Results are given in ppm by weight of soluble magnesium ions based on the total weight of calcium carbonate particulate matter.

[23] The total magnesium content of calcium carbonate particulate matter (including water-soluble magnesium ions and magnesium ions in the form of water-insoluble magnesium compounds or salts) is determined using X-ray fluorescence (XRF). The result is given as a percentage of MgO in the calcium carbonate material, and the content of Mg is calculated accordingly.

[24] The pH of the paint composition is determined using a standard pH meter such as a Mettler Toledo FiveEasy™ pH/mV Bench Meter.

[25] The viscosity of the paint composition is determined in the present disclosure using a Kinexus Pro+ at a temperature of 25° C. using conical (CP4/40 SR1877 SS) and plate (PLS61 S1555 SS) geometries. The measurement consists of three steps: (1) with an initial shear of 0.1 reciprocal second, measurements are taken for 30 seconds and values are recorded every second. (2) With a shear of 30 reciprocal seconds, measurements are taken for 30 seconds and values are re-recorded every second. The first two steps (1) and (2) essentially equilibrate the paint composition before the next step (3) is performed. (3) With a shear of 0.1 reciprocal seconds, measurements are taken for 30 minutes and values are recorded every 5 seconds. In the experimental part, the measurement is performed immediately after preparing the paint composition (T0), after 24 hours (T24), after 48 hours (T48), after 1 week (T1 week) and/or after 2 weeks (T2 week) It can be. All values are reported in Pa·s.

[26] The gel strength of a paint composition is determined in the present disclosure using an ICI gel strength viscometer. All values are reported in grams per centimeter.

[27] The low shear viscosity (0.3 to 30 s ^-1 ) (Brookfield viscosity) of the paint composition is determined in the present disclosure using Brookfield DV-II+ Pro. Brookfield viscosity was measured at 1 rpm, 10 rpm and 100 rpm, and values were taken after 1 minute. All values are reported in Poise. In this application, the term “viscosity” refers to a viscosity determined using a Kinexus Pro+ device as described above, whereas the term “Brookfield viscosity” refers to a value obtained by measurement using a Brookfield DV-II+ Pro device. refers to

[28] X-ray photoelectron spectroscopy is determined in the present disclosure using a Scienta-Omicron Argus analyzer and a monochromatic Al Kα (1486.7 eV) source operating at 225 W power as the x-ray source. The samples were mounted by pressing on indium foil to minimize differential packing of the powder. A charge neutralizer was used to quench the charge during XPS (2 μA at 1.5 eV). The wide-energy range (irradiation) scan was recorded with 50 eV pass energy and the narrow-range analytical scan was recorded with 20 eV pass energy. All intensities are corrected for the transfer function of the XPS instrument and energy scales are referenced internally to the foreign carbon bound to the powder surface.

[29] In the present disclosure, the total calcium carbonate content of the calcium carbonate particulate material is determined using a Methrom Titrando 905 and a Touch Control 900 (procedure: backtitration). For example, 2.200 g of calcium carbonate particulate matter and 140 ml of water are placed in a beaker and diluted with 6 mol/L nitric acid until a pH of 1.5 is reached. A dynamic titration is performed using 1 mol/l of sodium hydroxide until the equivalence point is reached. The consumption of nitric acid is calculated by the formula:

V1(HNO ₃ ) = V2(HNO ₃ ) - V(NaOH)

V1 (HNO ₃ ): Volume required to react with calcium carbonate in calcium carbonate particulate matter

V2 (HNO ₃ ): volume required to reach pH 1.5 in ml (step a)

V(NaOH): Volume required to react with excess HNO ₃ in ml and reach equivalence point (step b)

The weight percentage of calcium carbonate in the calcium carbonate particulate material is calculated according to the formula:

m (CCPM): initial weight of calcium carbonate particulate matter

V1 (HNO ₃ ): volume required to reach pH 1.5 in ml (step a)

V(NaOH): Volume required to react with excess HNO ₃ in ml and reach equivalence point (step b)

c(HNO ₃ ): concentration of HNO ₃ - 6 mol/l

c(NaOH): concentration of NaOH - 1 mol/l

[30] The d ₅₀ particle size of calcium carbonate particulate material is Micromeritics Instruments Corporation, Norcross, Georgia, USA, referred to herein as “Micromeritics Sedigraph 5100 Units”, Tel: +1 770 662 3620; Website: www.micromeritics.com ) is measured in a well-known manner by precipitation of calcium carbonate particulate matter in fully dispersed conditions in an aqueous medium using a Sedigraph 5100 machine supplied by These machines provide a plot and a measure of the cumulative weight percentage of particles having a size referred to in the art as the 'equivalent spherical diameter' (esd) that is less than a given esd value. The median particle size d ₅₀ is the value determined in this way of the particle esd in which 50% by weight of particles having an equivalent spherical diameter smaller than the d ₅₀ value are present.

calcium carbonate particulate matter

[31] The calcium carbonate particulate material according to the first aspect comprises less than about 170 ppm of water-soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water-soluble magnesium ions is determined using the method described herein.

[32] In some embodiments, the calcium carbonate particulate material is less than about 170 ppm, based on the total amount of calcium carbonate particulate matter, e.g., less than about 160 ppm, or less than about 150 ppm, based on the total amount of calcium carbonate particulate material. , or less than about 140 ppm, or less than about 130 ppm, or less than about 120 ppm, or less than about 110 ppm, or less than about 100 ppm, or less than about 90 ppm, or less than about 80 ppm of water-soluble magnesium ions.

[33] In one embodiment, the calcium carbonate particulate material contains less than about 120 ppm of water-soluble magnesium ions based on the total amount of the calcium carbonate particulate material. In another embodiment, the calcium carbonate particulate material comprises less than about 80 ppm water soluble magnesium ions based on the total amount of calcium carbonate particulate material.

[34] The solubility (in g/100 ml) of some magnesium salts is given in the table below:

Table 1:

[35] The calcium carbonate particulate material can be obtained from any source, eg, ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), or a combination thereof.

[36] The calcium carbonate particulate material used in the disclosure of the present invention may be ground calcium carbonate (GCC) generally obtained from natural sources by grinding. Ground calcium carbonate (GCC) is typically obtained by crushing and then grinding a mineral source such as chalk, marble or limestone to obtain a product with the desired degree of fineness, followed by a particle size classification step. It can be. Other techniques such as bleaching, flotation and magnetic separation may also be used to obtain a product with a desired degree of fineness and/or color. The particulate solid material may be ground autonomously, ie by friction between the particles of the solid material themselves, or alternatively, in the presence of a particulate grinding medium comprising particles of a material different from the calcium carbonate to be ground. Generally, this process can be carried out with or without a dispersant, which can be added at any stage of the process.

[37] Precipitated calcium carbonate (PCC) can also be used as a source of calcium carbonate particulate matter in the present disclosure and can be produced by any known method available in the art. TAPPI Monograph Series No 30, "Paper Coating Pigments", pages 34-35 describes three major commercial processes for making precipitated calcium carbonate that can be used in the practice of the present disclosure. In all three processes, the calcium carbonate feed material, such as limestone, is first calcined to produce quicklime, which is then calcined in water to produce calcium hydroxide or milk of lime. In the first process, milk of lime is directly carbonated with carbon dioxide gas. This process has the advantage that by-products are not formed and the properties and purity of the calcium carbonate product can be controlled relatively easily. In the second step, milk of lime is brought into contact with soda ash to produce a precipitate of calcium carbonate and a solution of sodium hydroxide by double cracking. When this process is used commercially, sodium hydroxide can be substantially completely separated from calcium carbonate. In a third major commercial process, milk of lime is first contacted with ammonium chloride to give a calcium chloride solution and ammonia gas. The calcium chloride solution is then contacted with soda ash to produce a solution of precipitated calcium carbonate and sodium chloride by double decomposition. Crystals can be produced in a variety of different shapes and sizes depending on the specific reaction process used. The three main types of PCC crystals are aragonite, rhombohedral and scalenohedral, all of which are suitable for use in the present disclosure, including mixtures thereof.

[38] In one embodiment, the calcium carbonate particulate material comprises ground calcium carbonate (GCC), for example, at least about 85 wt.% of GCC, or at least about 95% GCC, based on the total weight of the calcium carbonate particulate material. % GCC, or at least about 98 wt. % GCC, or the calcium carbonate particulate material essentially consists of GCC, for example, the calcium carbonate particulate material is GCC.

[39] In another embodiment, the calcium carbonate particulate material comprises precipitated calcium carbonate (PCC), for example, at least about 85 wt.% of PCC, or at least about 95 wt. % PCC, or at least about 98 wt. % PCC, or the calcium carbonate particulate material may consist essentially of PCC; for example, the calcium carbonate particulate material is PCC. This embodiment is preferred.

[40] In some embodiments, the calcium carbonate particulate material has a relatively high purity, for example, the calcium carbonate particulate material is greater than about 95 wt.%, for example about about 95 wt.%, based on the total weight of the calcium carbonate particulate material. Calcium carbonate in an amount greater than 98 wt.%.

[41] In an embodiment, the calcium carbonate particulate material has a particle size of about 10 μm or less, for example, about 8 μm or less, about 6 μm or less, about 4 μm or less, about 3.0 μm or less, about 3.0 μm or less, about 10 μm or less, as determined by Sedigraph. and an ad ₅₀ particle size of less than 2.5 μm, less than about 2.0 μm, or less than about 1.5 μm.

[42] Surprisingly, in the disclosure of the present invention, the total content of magnesium ions in the calcium carbonate particulate material, including water-soluble magnesium ions and magnesium ions in the form of non-water-soluble magnesium compounds or salts, is calcium carbonate according to the present disclosure. It has been found that it is not critical to the stability of paint compositions comprising particulate matter. Instead, it has been found that only the content of water-soluble magnesium ions in the calcium carbonate particulate material is related to the stability of paint compositions comprising calcium carbonate particulate material according to the present disclosure.

[43] It has also been found that water-soluble magnesium ions in the calcium carbonate particulate matter can be partially or entirely converted to magnesium ions in the form of non-water-soluble magnesium compounds or salts. Accordingly, the content of water-soluble magnesium ions in the calcium carbonate particulate matter can be reduced below a level at which the stability of the paint is not adversely affected without the need to reduce the total magnesium content of the calcium carbonate particulate matter. Thus, in certain embodiments, the ratio between the total magnesium content of the calcium carbonate particulate material and the content of soluble magnesium ions in the calcium carbonate particulate material, as determined using the methods described herein, is greater than or equal to about 1.5, e.g., about 2.0 or higher. That is, the total magnesium content of the calcium carbonate particulate material includes magnesium compounds that are insoluble in water according to the method described above.

[44] In one embodiment, the calcium carbonate particulate material comprises precipitated calcium carbonate (PCC), for example, the calcium carbonate particulate material comprises at least about 85 wt.% of PCC, based on the total weight of the calcium carbonate particulate material. , or at least about 95 wt.% PCC, or at least about 98 wt.% PCC, or the calcium carbonate particulate material consists essentially of PCC, or the calcium carbonate particulate material is PCC, and the calcium carbonate particulate material comprises less than about 170 ppm of water-soluble magnesium ions, based on the total amount of calcium carbonate particulate matter, for example, the calcium carbonate particulate material has less than about 150 ppm, or less than about 120 ppm, based on the total amount of calcium carbonate particulate matter. , or less than about 110 ppm, or less than about 100 ppm, or less than about 90 ppm, or less than about 80 ppm of water-soluble magnesium ions.

[45] In one embodiment, the calcium carbonate particulate material comprises precipitated calcium carbonate (PCC), for example, at least about 85 wt.% of PCC, or at least about 95% PCC, based on the total weight of the calcium carbonate particulate material. % PCC, or at least about 98 wt. % PCC, or the calcium carbonate particulate material consists essentially of PCC, or the calcium carbonate particulate material is PCC, and the calcium carbonate particulate material is a calcium carbonate particulate material. MgCl ₂ , MgBr ₂ , MgI ₂ , MgSO ₄ , Mg(acetate) ₂ , Mg(ClO ₃ ) ₂ , Mg(ClO ₄ ) ₂ , Mg(BrO ₃ ) ₂ , MgCr less than about 170 ppm based on the total amount of ₂ O ₇ , MgSiF ₆ , Mg(HCO ₂ ) ₂ , Mg(IO ₃ ) ₂ , MgMoO ₄ , MgS ₂ O ₃ and a water-soluble magnesium ion supplied from a magnesium salt selected from hydrates thereof, for example, The calcium carbonate particulate matter is less than about 150 ppm, or less than about 120 ppm, or less than about 110 ppm, or less than about 100 ppm, or less than about 90 ppm, based on the total amount of calcium carbonate particulate matter, as determined by the methods described herein. , or less than about 80 ppm magnesium ions.

process

[46] The present disclosure further provides a process for producing the calcium carbonate particulate material according to the first aspect.

[47] In one embodiment, the process,

- providing a calcium carbonate particulate material comprising at least about 170 ppm water soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water soluble magnesium ions is determined using the method described herein; and

- heating the calcium carbonate particulate material to a temperature of about 65° C. to about 200° C. for a period of up to about 24 hours.

[48] In an embodiment, the calcium carbonate particulate material having a water-soluble magnesium ion content of at least about 170 ppm based on the total amount of the calcium carbonate particulate material as measured by the method described herein is washed prior to heating.

[49] In another embodiment, the process,

- providing a calcium carbonate particulate material comprising at least about 170 ppm water soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water soluble magnesium ions is determined using the method described herein;

- washing the calcium carbonate particulate matter with water.

[50] In one embodiment, the process can be performed on a large scale, for example at a rate of production of calcium carbonate particulate matter of XYZ kg per hour. In such an embodiment, an efficient and cost effective process is accessible and often allows the use of existing equipment without the need for modification, eg the addition of a heating method.

[51] In one embodiment, the calcium carbonate particulate material having a water-soluble magnesium ion content of at least about 170 ppm based on the total amount of the calcium carbonate particulate matter as measured by the method described herein is for a period of about 24 hours or less after washing. It is heated to a temperature of about 65°C to about 200°C.

[52] In another embodiment, the process,

- providing a calcium carbonate particulate material comprising at least about 170 ppm water soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water soluble magnesium ions is determined using the method described herein;

- washing the calcium carbonate particulate matter with water; and

- heating the calcium carbonate particulate material after washing to a temperature of about 65° C. to about 200° C. for a period of up to about 24 hours.

[53] The following description applies to all processes according to the present invention unless explicitly stated to the contrary or the context dictates otherwise.

[54] The provided calcium carbonate particulate material may contain about 170 ppm or more and less than about 200 ppm of water-soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water-soluble magnesium ions is determined using the method described herein The crystallized or provided calcium carbonate particulate material may comprise at least about 200 ppm of soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of soluble magnesium ions is determined using the methods described herein.

[55] The characteristics of the calcium carbonate particulate material described herein are also characteristics of the process according to the present disclosure.

[56] In one embodiment, washing may be performed at a temperature of less than about 40°C, for example, from about 5°C to about 40°C, or from about 10°C to about 35°C, or from about 15°C to about 30°C. there is.

[57] In one embodiment, the washing is 1200 seconds or less, for example, about 120 seconds to about 1000 seconds, or about 180 seconds to about 860 seconds, or about 240 seconds to about 720 seconds, or about 360 seconds to about 660 seconds, or from about 440 seconds to about 560 seconds.

[58] In one embodiment, washing may be performed using water, eg, distilled water or tap water, eg, tap water.

[59] When the washing is performed using water, in one embodiment, the weight ratio between the calcium carbonate and the total volume of water used is about 1:500 to about 1:1, for example, about 1:250 to about 1:4, or from about 1:100 to about 1:9.

[60] In one embodiment, only one washing step is performed between providing the calcium carbonate particulate material and heating the calcium carbonate particulate material. In another embodiment, only one washing step is performed during the process.

[61] Heating of the calcium carbonate particulate material in the process according to the disclosure of the present invention may be performed using an air-swept mill. Suitable air-swept mills are available, for example, from Atritor Ltd., UK, their products generally designated as Atritor. In an embodiment, the calcium carbonate particulate material is heated using an air-swept mill, and the temperature of the material exiting the atritor is between about 65°C and about 220°C, such as between about 80°C and about 200°C. , or about 90°C to about 185°C, or about 100°C to about 175°C, or about 110°C to about 160°C, or about 120°C to about 150°C, or about 130°C to about 140°C. For heating using an air-swept mill, the duration of the heating step may be about 10 seconds or less, such as about 5.0 seconds or less, or about 1.0 seconds or less, or about 0.1 seconds or less.

[62] In an embodiment, the calcium carbonate particulate material is heated by conventional heating, for example, heating is performed using an oven, band dryer, spray dryer, CD dryer, etc., and the temperature is from about 65 ° C to about 220°C, such as about 90°C to about 210°C, or about 110°C to about 200°C, or about 120°C to about 190°C, or about 130°C to about 180°C, or about 140°C to about 170°C , or about 150°C to 160°C. When the calcium carbonate particulate material is heated by conventional heating, for example using an oven, the heating period is from about 2.0 hours to about 24 hours, such as from about 6.0 hours to about 22 hours, or about 12 hours. to about 20 hours, or about 14 to about 18 hours. When the calcium carbonate particulate material is heated using a band dryer, the heating period is from about 0.2 hours to about 2.0 hours, or from about 0.5 hours to about 1.8 hours, or from about 0.7 hours to about 1.5 hours, or from about 0.9 hours to about 1.2 hours. it could be time When the calcium carbonate particulate material is heated by a spray dryer or a CD dryer, the heating period is from about 0.5 minutes to about 10 minutes, or from about 1.0 minutes to about 9.5 minutes, or from about 1.5 minutes to about 9.0 minutes, or from about 2.0 minutes to about 9.5 minutes. about 7.0 minutes, or about 3.0 minutes to about 5.0 minutes. In the present disclosure, heating using an air-swept mill is not considered "conventional heating".

[63] In the embodiment, the calcium carbonate particulate material is heated by conventional heating, for example, the heating is performed using an oven, band dryer, spray dryer, CD dryer, etc., and the temperature (in ° C) during heating and time (in hours) satisfy the following relationship:

Temperature x time > 850℃·h

[64] In an embodiment, the calcium carbonate particulate material is washed before heating, and the calcium carbonate particulate material is heated by conventional heating, for example, heating using an oven, band dryer, spray dryer, CD dryer, etc. When heated, the temperature (in °C) and time (in hours) satisfy the following relationship:

Temperature x time > 850℃·h

[65] In an embodiment, the calcium carbonate particulate material is not washed before heating, and the calcium carbonate particulate material is heated by conventional heating, for example, heating using an oven, band dryer, spray dryer, CD dryer, etc. and the temperature (in °C) and time (in hours) during heating satisfy the following relationship:

Temperature x time > 1250℃·h

[66] In an embodiment, the heating is performed using an oven, and the temperature is between about 65°C and about 200°C, such as between about 90°C and about 190°C, or between about 110°C and about 180°C, or about 120°C. °C to about 180 °C, or about 130 °C to about 170 °C, or about 140 °C to about 160 °C, and/or the heating period is about 2.0 hours to about 24 hours, such as about 6.0 hours to about 22 hours. , or from about 12 hours to about 20 hours, or from about 14 hours to about 18 hours.

[67] In an embodiment, drying is performed using an oven.

Calcium carbonate particulate material obtainable by the process according to the present disclosure

[68] As already outlined above, the disclosure of the present invention also relates to a calcium carbonate particulate material obtainable by the process according to the disclosure of the present invention. Features and embodiments of the calcium carbonate particulate material according to the present disclosure are also features and embodiments of the calcium carbonate particulate material obtainable by the process according to the present disclosure.

paint composition

[69] The present disclosure further relates to a paint composition comprising the calcium carbonate particulate material according to the present disclosure or the calcium carbonate particulate material obtainable by a process according to the present disclosure. In the following, "calcium carbonate particulate material according to the present disclosure" and "calcium carbonate particulate material obtainable by a process according to the present disclosure" are abbreviated for brevity by the term "calcium carbonate particulate material".

[70] In an embodiment, the paint composition comprises about 1.0 wt.% to about 60 wt.% of a calcium carbonate particulate material based on the total weight of the paint composition, for example, about 5.0 wt.% based on the total weight of the paint composition. .% to about 50 wt.%, or about 10 wt.% to about 45 wt.%, or about 15 wt.% to about 40 wt.%, or about 20 wt.% to about 35 wt.% calcium carbonate Contains particulate matter.

[71] In the embodiment, the paint composition further includes water glass. Water glass, when present, in an amount of about 5.0 wt.% or less, based on the total weight of the paint composition, for example, in an amount of about 1.0 wt.% to about 4.5 wt.%, based on the total weight of the paint composition, or in an amount from about 2.0 wt.% to about 4.0 wt.%, or from about 2.1 wt.% to about 3.5 wt.%, such as from about 2.1 wt.% to about 5.0 wt.%, or about 2.1 wt.% % to about 4.5 wt.%, or about 2.1 wt.% to about 4.0 wt.%, or about 2.1 wt.% to about 3.5 wt.%, or about 2.1 wt.% to about 3.0 wt.%. can exist

[72] In the disclosure of the present invention, the amount of water glass is provided as the active solid of water glass based on the total weight of the paint composition. Thus, for example, if a water glass solution containing 25 wt.% active solids is used, 8 wt.% of this solution is used to achieve a water glass amount of 2 wt.%.

[73] In an embodiment, a paint composition according to the present disclosure is characterized by a viscosity increase from T0 to T24, each determined after 1800 seconds in step (3) of viscosity measurement described herein of less than about 100 Pa s. .

[74] In an embodiment, the paint composition according to the disclosure of the present invention is less than about 120 Pa s, for example, less than about 105 Pa s, or less than about 90 Pa s, or less than about 75 Pa s Characterize the viscosity determined after T24 and 1800 seconds in step (3) of the viscosity measurement described herein.

[75] In an embodiment, the paint composition according to the disclosure of the present invention has less than about 20 Pa s, for example, less than about 18 Pa s, or less than about 15 Pa s, or less than about 12 Pa s, or a viscosity determined after T0 and 1800 seconds in step (3) of viscosity measurement described herein of less than about 10 Pa·s, or less than about 8 Pa·s.

[76] The paint composition according to the disclosure of the present invention may be characterized by the viscosity determined after T1 week and 1800 seconds in step (3) of the viscosity measurement described herein. The significant decrease in viscosity determined at week T1 compared to T24 may be due to degradation of the paint composition. Many examples according to the present invention do not exhibit this decomposition pattern.

[77] In an embodiment, the paint composition further includes a polymer sometimes referred to as a “binder”. These polymers are the film-forming components of paints that impart adhesion and bind pigments together. Thus, a polymer is any suitable material capable of binding pigments together and providing adhesion to a substrate painted with a paint. Polymers include natural and/or synthetic resins such as latex-based polymers and acrylic and/or vinyl based copolymers, polyurethanes, polyesters, melamine resins, epoxies, vinyl acetates, vinyl esters and ethylene based copolymers, and /or oils and other suitable monomeric species. For oil-based paints, suitable binders include linseed oil, tung oil or alkyd resins.

[78] The polymer may be used in solid form or in the form of a solution or dispersion in a solvent. In one embodiment, the binder is used as a dispersion in a solvent, such as water. For example, the solids content of such dispersions in water is from about 25 wt.% to about 75 wt.%, based on the total weight of the dispersion, for example from about 35 wt.% to about 65 wt.%, or from about 45 wt.% to about 55 wt.%.

[79] In one embodiment, the amount of polymeric solids present in the paint composition is from about 2.0 wt.% to about 25 wt.%, based on the total weight of the paint composition, for example, about 3.0 wt.% to about 20 wt.%, or about 4.0 wt.% to about 15 wt.%, or about 5.0 wt.% to about 10 wt.%.

[80] In an embodiment, the paint composition has a pH value of about 8.5 or greater. The pH value of the paint composition may be less than about 11.4. In an embodiment, the paint composition has a pH value from about 8.5 to about 11.4, such as from about 9.5 to about 11.4, or from about 10.5 to about 11.4, or from about 11.0 to about 11.4.

[81] The pH can be adjusted if necessary using bases common in the field of paint manufacture, such as alkali metal hydroxides, ammonia and AMP (2-amino-2-methyl-1-propanol).

[82] In an embodiment, the paint composition further includes a base that may be selected from the group consisting of alkali metal hydroxide, ammonia, and AMP (2-amino-2-methyl-1-propanol).

[83] In an embodiment, the alkali metal hydroxide is selected from the group consisting of sodium hydroxide and potassium hydroxide. In an embodiment, the base is selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonia and AMP (2-amino-2-methyl-1-propanol) and combinations thereof. The amount and concentration of base is chosen to obtain the desired pH value.

[84] In an embodiment, the paint composition further includes one or more pigment(s) and/or one or more filler(s). A pigment is what provides the primary coloration of a paint, whether white or tinted. The term includes liquid vehicles, i.e. finely divided natural or synthetic inorganic or organic insoluble dispersed particles which can be dispersed in a solvent.

[85] Suitable pigments include, for example, titanium dioxide, carbon black, calcium sulfate, iron oxide, and copper-complex phthalo blue. Other suitable pigments for providing color will be readily apparent to those skilled in the art.

[86] Suitable fillers are, for example, gypsum, hydrous candite clays such as kaolin, halloysite or ball clays, anhydrous (calcined) candite clays such as metakaolin or fully calcined kaolin. , talc, mica, perlite, feldspar, nepheline syenite, wollastonite, diatomaceous earth, barite, glass, and natural or synthetic silica or silicates.

[87] In an embodiment, the one or more pigment(s) and the one or more filler(s), if present, are different from the calcium carbonate. In a further embodiment, the one or more pigment(s) and one or more filler(s), if present, are free of calcium carbonate.

[88] In an embodiment, the one or more pigment(s) and one or more filler(s), when present, are from about 1.0 wt.% to about 50 wt.%, based on the total weight of the paint composition, for example, from about 2.5 wt.% to about 40 wt.%, or from about 5.0 wt.% to about 30 wt.%, based on the total weight of the paint composition.

[89] In an embodiment, the solids content of the paint composition is about 25 wt.% to about 75 wt.%, for example, about 35 wt.% to about 65 wt.%, based on the total weight of the paint composition, or from about 45 wt.% to about 55 wt.%.

[90] In principle, any solvent suitable for a paint composition may be used in a paint composition according to the present disclosure. In an embodiment, the paint composition is a water-based composition, and the water content of the paint composition is from about 25 wt.% to about 75 wt.%, for example from about 35 wt.% to about 65 wt.%, based on the total weight of the paint composition. wt.%, or from about 45 wt.% to about 55 wt.%.

[91] In an embodiment, the paint composition is essentially free of organic biocides. In some instances, the paint composition is essentially free of an organic biocide having a molecular weight of less than about 500 g/mol, for example, the paint composition is essentially free of an organic biocide having a molecular weight of less than about 1000 g/mol. agent, the paint composition is essentially free of organic biocides having a molecular weight of less than about 2000 g/mol, or the paint composition is essentially free of organic biocides having any molecular weight. In this context, "essentially free" means that the content of the organic biocide detected from a sample of the paint composition using gas chromatography mass spectrometry or liquid chromatography mass spectrometry is about 10 ppm based on the total weight of the paint composition. less than, eg, an amount of less than about 5 ppm based on the total weight of the paint composition or less than about 2.5 ppm based on the total weight of the paint composition. These small amounts of organic biocides may be present in paint compositions because some of the components used to prepare the paint compositions cannot otherwise be stabilized. In one embodiment, the organic biocide is not added to the paint composition as a separate excipient.

[92] The exemplary paint disclosed herein also includes, for example, at least one additive selected from conventional additives such as surfactants, thickeners, antifoam wetting agents, dispersants, solvents, and coalescents, as well as other functional additives. can do. These additives are well known in the art. In embodiments, the total amount of conventional additives, based on the total weight of the paint composition, does not exceed about 10 wt. %, for example, the total amount of conventional additives, based on the total weight of the paint composition, is about 0.10 wt. % to about 7.5 wt.%, or about 0.25 wt.% to about 5.0 wt.% or about 0.50 wt.% to about 2.5 wt.%. When solutions of these additives are used, the above amounts relate to the additive itself without solvent.

[93] In an embodiment, the paint composition includes, based on the total weight of the paint composition:

- from about 1.0 wt.% to about 60 wt.%, for example from about 5.0 wt.% to about 50 wt.%, or from about 10 wt.% to about 45 wt.%, or from about 15 wt.% to about 40 wt.%, or about 20 wt.% to about 35 wt.% of calcium carbonate particulate matter;

- in an amount of about 5.0 wt.% or less, for example in an amount of about 1.0 wt.% to about 4.5 wt.%, or in an amount of about 2.0 wt.% to about 4.0 wt.%, or in an amount of about 2.1 wt.% to about 3.5 wt.%, for example about 2.1 wt.% to about 5.0 wt.%, or about 2.1 wt.% to about 4.5 wt.%, or about 2.1 wt.% to about 4.0 wt.%, or about water glass in an amount of from 2.1 wt.% to about 3.5 wt.%, or from about 2.1 wt.% to about 3.0 wt.%;

- the amount of polymeric solids present in the paint composition is from about 2.0 wt.% to about 25 wt.%, such as from about 3.0 wt.% to about 20 wt.%, or from about 4.0 wt.% to about 15 wt. %, or from about 5.0 wt.% to about 10 wt.% of the polymer;

- optionally, calcium carbonate in an amount of from about 1.0 wt.% to about 50 wt.%, for example from about 2.5 wt.% to about 40 wt.%, or from about 5.0 wt.% to about 30 wt.%; and one or more different pigment(s) and one or more filler(s);

- optionally, the amount of conventional additives not exceeding about 10 wt.%, or the total amount of conventional additives is from about 0.10 wt.% to about 7.5 wt.%, for example from about 0.25 wt.% to about 5.0 wt.%, or within the range of about 0.50 wt.% to about 2.5 wt.%;

- water added up to 100 wt.%;

wherein the paint composition has a pH value of from about 8.5 to about 11.4, such as from about 9.5 to about 11.4, or from about 10 to about 11.4, or from about 11.0 to about 11.4;

The calcium carbonate particulate material comprises precipitated calcium carbonate (PCC), for example, at least about 85 wt. % PCC, or at least about 95 wt. % PCC, or at least about 95 wt. % PCC, based on the total weight of the calcium carbonate particulate material. 98 wt. %, or at least about 99 wt. % of PCC, or the calcium carbonate particulate material consists essentially of PCC, eg, the calcium carbonate particulate material is PCC.

[94] For the avoidance of doubt, this application is directed to the subject matter described in the numbered paragraphs below.

1. Calcium carbonate particulate material comprising less than about 170 ppm water-soluble magnesium ions, based on the total amount of calcium carbonate particulate material, wherein the amount of water-soluble magnesium ions is determined using the method described herein. .

2. The carbonic acid of numbered paragraph 1, comprising less than about 160 ppm water-soluble magnesium ions based on the total amount of calcium carbonate particulate matter, wherein the amount of water-soluble magnesium ions is determined using the method described herein. Calcium particulate matter.

3. The carbonic acid of numbered paragraph 2, comprising less than about 120 ppm soluble magnesium ions based on the total amount of calcium carbonate particulate matter, wherein the amount of soluble magnesium ions is determined using the method described herein. Calcium particulate matter.

4. The calcium carbonate particulate material according to numbered paragraph 3, wherein the water-soluble magnesium ions are supplied from one or more magnesium salt(s).

5. Numbered paragraphs 4, wherein the one or more water-soluble magnesium salt(s) are MgCl ₂ , MgBr ₂ , MgI ₂ , MgSO ₄ , Mg(acetate) ₂ , Mg(ClO _{3 )} , based on the total amount of calcium carbonate particulate matter. ) ₂ , Mg(ClO ₄ ) ₂ , Mg(BrO ₃ ) ₂ , MgCr ₂ O ₇ , MgSiF ₆ , Mg(HCO ₂ ) ₂ , Mg(IO ₃ ) ₂ , MgMoO ₄ , MgS ₂ O ₃ and their hydrates Calcium carbonate particulate material selected from.

6. The calcium carbonate particulate material of any one of numbered paragraphs 1-5, wherein the calcium carbonate particulate material is ground calcium carbonate, precipitated calcium carbonate or a combination thereof.

7. The calcium carbonate particulate material according to any of the numbered paragraphs 1 to 6, wherein the calcium carbonate particulate material is precipitated calcium carbonate.

8. The calcium carbonate particulate material of any of numbered paragraphs 1-7, comprising calcium carbonate in an amount greater than about 95 wt.%, based on the total weight of the calcium carbonate particulate material.

9. A calcium carbonate particulate material according to any of numbered paragraphs 1-8 having an ad ₅₀ particle size of less than or equal to about 3.0 μm as measured by sedimentation using a Sedigraph.

10. A process for preparing a calcium carbonate particulate material according to any one of numbered paragraphs 1 to 9,

- providing a calcium carbonate particulate material comprising at least about 170 ppm, for example at least about 200 ppm, of water-soluble magnesium ions, based on the total amount of calcium carbonate material, wherein the amount of water-soluble magnesium ions is described herein is determined using;

- heating the calcium carbonate particulate material to a temperature of about 65° C. to about 200° C. for a period of up to about 24 hours.

11. The method of numbered paragraph 10 wherein the calcium carbonate particulate material is washed prior to heating.

12. A process for preparing a calcium carbonate particulate material according to any one of numbered paragraphs 1 to 9,

- providing a calcium carbonate particulate material comprising at least about 170 ppm, for example at least about 200 ppm, of water-soluble magnesium ions, based on the total amount of calcium carbonate material, wherein the amount of water-soluble magnesium ions is described herein is determined using; and

- washing the calcium carbonate particulate matter with water.

13. The method of numbered paragraph 12, wherein the calcium carbonate particulate material is heated to a temperature of about 65° C. to about 200° C. for a period of up to about 24 hours after washing.

14. A process for preparing a calcium carbonate particulate material according to any one of numbered paragraphs 1 to 9, comprising:

- providing a calcium carbonate particulate material comprising at least about 170 ppm, for example at least about 200 ppm, of water-soluble magnesium ions, based on the total amount of calcium carbonate material, wherein the amount of water-soluble magnesium ions is described herein is determined using;

- washing the calcium carbonate particulate matter with water; and

- heating the calcium carbonate particulate material after washing to a temperature of about 65° C. to about 200° C. for a period of up to about 24 hours.

15. The method of any one of numbered paragraphs 11 to 14 wherein washing is performed at a temperature of 25° C. with water.

16. Any of the numbered paragraphs 10, 11, and 13 to 15, when depending on any of the numbered paragraphs 10, 11, 13 and 14, the temperature in degrees Celsius during heating, and the time How a unit of time satisfies the relationship:

Temperature x time > 850℃·h

17. A calcium carbonate particulate material obtainable by a process according to any of numbered paragraphs 10 to 16.

18. A paint composition comprising a calcium carbonate particulate material according to any one of numbered paragraphs 1 to 9, or numbered paragraph 17.

19. The paint composition according to numbered paragraph 18, further comprising water glass.

20. The paint composition of numbered paragraph 19, wherein the water glass is present in an amount of about 5.0 wt.% or less, based on the total weight of the paint composition.

21. The paint composition of any one of numbered paragraphs 18-20 having a pH value of about 8.5 or greater.

22. The paint composition of any one of numbered paragraphs 18-21, further comprising a polymer.

23. The paint composition of any one of numbered paragraphs 18-22, further comprising a base.

24. The paint composition according to numbered paragraph 23, wherein the base is selected from the group consisting of alkali metal hydroxides, ammonia, AMP (2-amino-2-methyl-1-propanol) and combinations thereof.

25. The paint composition according to numbered paragraph 24, wherein the alkali metal hydroxide is selected from the group consisting of sodium hydroxide and potassium hydroxide.

26. The paint composition of any of numbered paragraphs 18-25, further comprising one or more pigment(s) and/or one or more filler(s).

27. The paint composition according to any one of numbered paragraphs 18-26, which is a water based composition.

28. The paint composition according to any one of numbered paragraphs 18 to 27, which is essentially free of organic biocides.

29. The paint composition of numbered paragraph 28, wherein the organic biocide has a molecular weight of less than or equal to about 500 g/mol.

Example

[95] ingredient:

-SE Tylose GmbH & Co. Tylose MH 30000 YP4, a water soluble, nonionic, methyl hydroxyethyl cellulose thickener available from KG;

- Lopon 890, a dispersant obtainable from ICL Advanced Additives;

- ammonia with a concentration of 28 wt.%;

- Agitan 218, an antifoaming agent for aqueous emulsions obtainable from Munzing Chemie;

- Mowilith LDM 1828, an aqueous copolymer dispersion based on vinyl acetate, vinyl ester and ethylene, obtainable from Celanese Emulsion Polymers (solids content about 50 wt.%);

- Trasol KE-K (water glass), a potassium silicate containing 28 wt.% of active solids obtainable from BASF;

- a test substance that is a calcium carbonate particulate material specified in each example;

- MgCl ₂ 6 H ₂ O;

- Mg(OH) ₂ ;

[96] Tylose MH 30000 YP4 thickener was made into a 2% solution 24 hours before paint makedown.

[97] Make-down method according to the order of addition listed in Table 2:

- Weigh all ingredients listed with 'Addition Sequence #1' into a high-speed mixer pot with a volume of 40 ml.

- The pot is then mixed for 1 minute at 3000 rpm using a SpeedMixer™ Model DAC 150.1 FVZ. A palette knife is used to scrape the powder off the rim of the pot and break up any large agglomerates as is customary in the art;

- mixing is then continued at 3000 rpm for 2 minutes and scraped again with a palette knife;

- A final 3 minute mixing at 3000 rpm completes the mill base dispersion.

- Weigh the ingredients listed with Step #2 into a pot, then mix for 1 minute at 2000 rpm;

- then weigh the compound into the pot with step #3, then mix for 1 minute at 2000 rpm;

- Finally, weigh the ingredients into the pot with step #4 and give the paint a final mix at 2000 rpm for 2 minutes;

Table 2:

Table 3:

Example 1:

[98] In this Example, ImeXtend 90, a GCC material obtainable from Imerys, was used as a test material. In addition, to test the effect of water-soluble and water-insoluble magnesium present in the paint composition, 5.66 grams of water used in the let down according to Table 2 were mixed with appropriate amounts of MgCl ₂ .6H ₂ O and Mg(OH) ₂ , respectively. MgCl ₂ .6H ₂ O _or Mg by replacing with an aqueous solution containing MgCl ₂ .6H ₂ O or Mg (OH) ₂ was included in the paint composition. In Tables 4 and 5, respectively, after step (2) of the viscosity measurement described herein (“30 seconds at 30 shear”) and during step (3) after 5, 30, 60, 120, 900 and 1800 seconds (“0.1 Viscosity values of "in shear") are given. In addition, the measurement was performed immediately after preparing the paint composition (T0), after 24 hours (T24), after 48 hours (T48), after 1 week (T1 week) and after 2 weeks (T2 week) (MgCl ₂ .6H ₂ O case) is performed.

Table 4 (Addition of MgCl ₂ .6H ₂ O):

Table 5 (addition of Mg(OH) ₂ ):

[99] As evidenced by the results provided in Table 4 above, the addition of water-soluble magnesium salt (MgCl ₂ .6H ₂ O) to the paint increases the content of water-soluble magnesium ions, resulting in increased viscosity. After 2 days a decrease in viscosity is observed for paint compositions with target amounts of 200 ppm and 1000 pm of water-soluble magnesium ions (see eg T48 vs. T1 weeks). Without wishing to be bound by theory, it is hypothesized that the paint becomes unstable and the structure of the paint composition begins to collapse.

[100] However, as demonstrated by Table 5, even a paint composition having a target amount of magnesium of 1000 ppm by the addition of Mg(OH) ₂ has a lower viscosity compared to a paint containing only ImeXtend 90 (“no addition”). show no significant increase. This is explained by the fact that magnesium hydroxide is practically insoluble in water (the solubility of Mg(OH) ₂ in water is only 9.628 x 10 ^-4 g/100 ml). Thus, the addition of Mg(OH) ₂ does not significantly increase the total amount of soluble magnesium ions since the magnesium remains in the form of magnesium hydroxide.

[101] These results show that the total content of magnesium ions, regardless of whether they are water-soluble or not, is not critical to the stability of the paint, and only the content of water-soluble magnesium ions affects the stability of the paint.

Example 2:

[102] In this example, Socal P2, a precipitated calcium carbonate obtainable by Imerys, optionally pretreated, was used as a test substance in the formulation according to Table 2. In Example 2, no addition of magnesium ions occurred.

[103] In particular, Socal P2 was pretreated as follows:

Sample 2A: Untreated, ie, Socal P2 was used as is, and the content of water-soluble magnesium ions was 170 ppm;

Sample 2B: Socal P2 from production under slurry was washed at room temperature with tap water in a calcium carbonate slurry:water volume ratio of about 1.5:10 for 500 seconds, subsequently dried in an oven at 150° C. for 16 hours, soluble magnesium ions The content of was 9 ppm;

Sample 2C: Socal P2 was dried in an oven at 150° C. for 16 hours without prior washing, and the content of soluble magnesium ions was 72 ppm;

Sample 2D: Socal P2 was washed as in the case of sample 2B, but instead of oven drying, drying was performed using an Atritor with an outlet temperature of 130°C and a drying time of about a few seconds or less, and water-soluble magnesium The content of ions was 53 ppm;

Sample 2E: Socal P2 was dried without prior washing using an atliter with an outlet temperature of 130° C. and a drying time of less than about a few seconds, and the content of soluble magnesium ions was 171 ppm;

[104] In Table 6 below, during step (3) after step (2) of the viscosity measurement described herein (“30 seconds at 30 shear”) and after 5, 30, 60, 120, 900 and 1800 seconds (“ at 0.1 shear") viscosity values are given. In addition, the measurement is performed immediately after preparing the paint composition (T0), after 24 hours (T24), after 48 hours (T48) and after one week (T1 week).

Table 6:

[105] As can be seen in Samples 2B and 2D, washing reduces the content of soluble magnesium ions in Socal P2, resulting in improved viscosity shown in Table 6 above. In addition, sample 2C, which was subjected to only oven drying without washing, showed a significantly reduced amount of soluble magnesium ions and also improved viscosity results compared to untreated Socal P2 (sample 2A). Without wishing to be bound by theory, it is assumed that some of the water-soluble magnesium ions are converted to a water-insoluble form by overdrying, and the resulting water-insoluble form of magnesium ions no longer affects the viscosity of the paint composition.

Example 3:

[106] In this Example, Socal P2 previously used in Example 2 was used as a test substance in the formulation according to Table 2. In Example 3, no addition of magnesium ion occurred.

[107] Except for the reference material, i.e., pure Socal P2 (Sample 3A), in Samples 3B to 3E, Socal P2 was washed at room temperature using tap water in a calcium carbonate slurry:water volume ratio of 1.5:10 for 500 seconds. , and subsequently dried in an oven, whereby the drying time and temperature were as follows:

Sample 3B: 80° C. for 16 hours, the content of soluble magnesium ions was 66 ppm;

Sample 3C: 105° C. for 16 hours, the content of soluble magnesium ions was 61 ppm;

Sample 3D: 150° C. for 16 hours, the content of soluble magnesium ions was 30 ppm;

Sample 3E: 150° C. for 6 hours, the content of soluble magnesium ions was 48 ppm;

[108] In Table 7 below, after step (2) of the viscosity measurement described herein ("30 seconds at 30 shear") and during step (3) after 5, 30, 60, 120, 900 and 1800 seconds (" at 0.1 shear") viscosity values are given. In addition, the measurement is performed immediately after preparing the paint composition (T0), after 24 hours (T24), after 48 hours (T48) and after one week (T1 week).

Table 7:

The results presented in Table 7 demonstrate that even after washing, the content of water-soluble magnesium ions can be further reduced by drying. As already discussed with respect to Example 2 above, and without wishing to be bound by theory, some of the water-soluble magnesium ions are converted to a water-insoluble form by drying, and this resulting water-insoluble form of magnesium ions is no longer part of the paint composition. It is assumed that it does not affect the viscosity.

Example 4:

[109] In this example, Socal P2, previously used in Examples 2 and 3, was used as a test substance in the following paint formulation:

Water/other additives: 38 wt.%

Pigment: 17 wt.%

Calcium carbonate: 20 wt.%

Binder: 25 wt.%

In Example 4, no addition of magnesium ion occurred.

[110] The reference material, i.e., pure Socal P2 (Sample 4A), was untreated. In Sample 4B, the Socal P2 was washed at room temperature using tap water in a 1.5:10 calcium carbonate slurry:water by volume ratio for 500 seconds. No drying was performed.

[111] The gel strength and Brookfield viscosity of samples 4A and 4B were measured immediately after the paint composition was prepared (T0), after 24 hours (T24), after 48 hours (T48), after 72 hours (T72) and after 1 week ( T1 week) was determined. Results are provided in the table below.

Table 8:

Example 5:

[112] In this example, pure Socal P2 was used as sample 5A, and Socal P2 washed with tap water in a calcium carbonate slurry:water volume ratio of 1.5:10 at room temperature for 500 seconds was used as sample 5B. In Example 5, no addition of magnesium ions occurred.

[113] Different magnesium species contained therein were identified using XPS spectroscopy. The table provides the atomic concentrations of Mg ²⁺ and Cl ⁻ ions associated with various species. They are all expressed in terms of calcium content, ie [Mg ²⁺ ] per Ca ²⁺ ion.

Table 9:

[114] Mg species assignment was partially performed using the Mg 2s peak as described by Ardizzone et al. , Appl. Surf. Sci. 119, 253 (1997)].

[115] It appears that the washing step removed all MgCl ₂ and MgCO ₃ species and reduced the remaining Mg(OH) ₂ concentration of the powder by approximately half.

Example 6:

[116] In this Example, Socal P2, which was already in the previous Example, was used as a test substance in the same formulation as that used in Example 4. In Example 4, no addition of magnesium ion occurred.

[117] Except for the reference material, namely pure Socal P2 (Sample 6A, water-soluble Mg content 170 ppm), in Samples 6B to 6E, Socal P2 was treated as follows, and the content of water-soluble magnesium was as described herein. It was decided as:

Table 10:

[118] The gel strength and Brookfield viscosity of Samples 6A to 6E were determined immediately after the paint composition was prepared (T0), after 24 hours (T24), after 48 hours (T48) and after 1 week (T1 week). Results are provided in the table below.

Table 11:

Claims (15)

A calcium carbonate particulate material comprising less than about 170 ppm water soluble magnesium ions based on the total amount of calcium carbonate particulate material, wherein the amount of water soluble magnesium ions is determined using the method described herein. 2. The calcium carbonate particulate material according to claim 1, wherein the water-soluble magnesium ions are supplied from one or more magnesium compounds or salt(s). 3. The method of claim 2, wherein the one or more water-soluble magnesium salt(s) is MgCl ₂ , MgBr ₂ , MgI ₂ , MgSO ₄ , Mg(acetate) ₂ , Mg(ClO ₃ ) ₂ , Mg, based on the total amount of calcium carbonate particulate matter. Carbonic acid selected from (ClO ₄ ) ₂ , Mg(BrO ₃ ) ₂ , MgCr ₂ O ₇ , MgSiF ₆ , Mg(HCO ₂ ) ₂ , Mg(IO ₃ ) ₂ , MgMoO ₄ , MgS ₂ O ₃ and their hydrates. Calcium particulate matter. 4. The calcium carbonate particulate material according to any one of claims 1 to 3, wherein the calcium carbonate particulate material is ground calcium carbonate, precipitated calcium carbonate or a combination thereof. 5. Calcium carbonate particulate material according to any one of claims 1 to 4, comprising calcium carbonate in an amount greater than about 95 wt.%, based on the total weight of the calcium carbonate particulate material. 6. The particulate material of any one of claims 1 to 5, wherein the calcium carbonate particulate material has an ad ₅₀ particle size of less than or equal to about 10.0 μm as measured by sedimentation using a Sedigraph. A process for preparing the calcium carbonate particulate material according to any one of claims 1 to 6,
- providing a calcium carbonate particulate material comprising at least about 170 ppm water soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water soluble magnesium ions is determined using the method described herein; and
- heating the calcium carbonate particulate material to a temperature of about 65° C. to about 200° C. for a period of up to about 24 hours,
method. 8. The method of claim 7 wherein the calcium carbonate particulate material is washed prior to heating. A process for preparing the calcium carbonate particulate material according to any one of claims 1 to 6,
- providing a calcium carbonate particulate material comprising at least about 170 ppm water soluble magnesium ions based on the total amount of calcium carbonate material, wherein the amount of water soluble magnesium ions is determined using the method described herein; and
- washing the calcium carbonate particulate matter with water,
method. 10. The method of claim 9, wherein the calcium carbonate particulate material is heated to a temperature of about 65°C to about 200°C for a period of up to about 24 hours after washing. 11. The method of any one of claims 8 to 10, wherein washing is performed at a temperature of about 25° C. using water. A calcium carbonate particulate material obtainable by the process according to any one of claims 6 to 11. A paint composition comprising the calcium carbonate particulate material according to any one of claims 1 to 6 or 12. 14. The paint composition of claim 13, further comprising water glass, optionally wherein the water glass is present in an amount of about 5.0 wt.% or less, based on the total weight of the paint composition. The method of claim 13 or 14, wherein the paint composition,
(a) has a pH value of about 8.5 or greater;
(b) essentially free of organic biocides;
paint composition.